An Edge-assisted, Object-oriented Random Forest Approach for Refined Extraction of Tea Plantations Using Multi-temporal Sentinel-2 and High-resolution Gaofen-2 Imagery

As a consumed and influential natural plant beverage,tea is widely planted in subtropical and tropical areas all over the world.Affected by(sub)tropical climate characteristics,the underlying surface of the tea distribution area is extremely complex,with a variety of vegetation types.In addition,tea distribution is scattered and fragmentized in most of China.Therefore,it is difficult to obtain accurate tea information based on coarse resolution remote sensing data and existing feature extraction methods.This study proposed a boundary-enhanced,object-oriented random forest method on the basis of high-resolution GF-2 and multi-temporal Sentinel-2 data.This method uses multispectral indexes,textures,vegetable indices,and variation characteristics of time-series NDVI from the multi-temporal Sentinel-2 imageries to obtain abundant features related to the growth of tea plantations.To reduce feature redundancy and computation time,the feature elimination algorithm based on Mean Decrease Accuracy(MDA)was used to generate the optimal feature set.Considering the serious boundary inconsistency problem caused by the complex and fragmented land cover types,high resolution GF-2 image was segmented based on the MultiResolution Segmentation(MRS)algorithm to assist the segmentation of Sentinel-2,which contributes to delineating meaningful objects and enhancing the reliability of the boundary for tea plantations.Finally,the object-oriented random forest method was utilized to extract the tea information based on the optimal feature combination in the Jingmai Mountain,Yunnan Province.The resulting tea plantation map had high accuracy,with a 95.38%overall accuracy and 0.91 kappa coefficient.We conclude that the proposed method is effective for mapping tea plantations in high heterogeneity mountainous areas and has the potential for mapping tea plantations in large areas.

Optimization of Supercritical Extraction Process of Laoshan Black Tea by Response Surface Methodology

[Objectives]Laoshan black tea was subjected to supercritical CO_(2) extraction. [Methods]The extraction conditions of Laoshan black tea were studied by an orthogonal experiment and optimized by response surface methodology. [Results] The optimum extraction conditions of black tea extract by supercritical CO_(2) extraction were as follows: extraction pressure 23.53 MPa, extraction time 1.73 h, and extraction temperature 49.75 ℃, with which the extract yield could reach 5.15% theoretically. [Conclusions] Based on the traditional extraction process, a supercritical extraction method optimized by response surface methodology and a unique extraction process were formed, which enriches the extraction processes and methods of natural raw materials.

Water Bath Extraction Optimization of Polyphenols from Qing Brick Tea and Raw Material Selection for Tea Polyphenol Extraction

In this paper,single-factor experiments and orthogonal experiment were conducted to optimize the water bath extraction of polyphenols from Qing Brick Tea,and the optimal extraction conditions obtained were as follows:solvent of 50%ethanol,solid/liquid ratio of 1∶30,temperature of 80℃,and time of 6 min.Under the optimal water bath extraction conditions,polyphenols in fresh tea leaves,fresh tea petioles,fresh tea blades,finished brick tea,finished tea petioles,finished tea blades,tea dregs after brewing and tea dregs after boiling were extracted,respectively.It was found that the quality fraction of polyphenols extracted from fresh tea leaves was the highest,with the best extraction effect.The extraction effect of leaf blades was better than that of leaf petioles,and the extraction effect of tea dregs after brewing was better than that of tea dregs after boiling.

Study on Extraction Technology of Theabrownine from Liubao Tea and Its Antioxidant Activity

[ Objective] This study aimed to provide theoretical reference for the extraction of theabrownine from Liubao tea, determination of the biological activity, and development and utilization of theabrownine. [Method] Orthogonal experimental design was adopted to investigate the effects of solid-liquid ratio, extraction temperature, extraction duration, and extraction frequency on the yield of theabrownine extracted from Liubao tea. The extraction technology was optimized, and the antioxidant activity of theabrownine was analyzed. [ Result] The results showed that extraction frequency and extraction temperature had significant effects on the yield of theabrownine extracted from Liubao tea, while solid-liquid ratio and extraction duration had no significant effect. The optimal conditions for extracting theabrownine from Liubao tea were determined as follows ： solid-liquid ratio was 1 ： 30, extraction temperature was 100℃, extraction duration was 80 min, and extraction frequency was 4 times. Under these conditions, the yield of theabrownine reached 22.92%. Results of antioxidant activity determination showed that hydroxyl radical-scavenging activity of theabrownine was as high as 74%, and the scavenging effects was significantly higher than that of Vitamin C under low concentrations; nitroso-scavenging activity of theabrownine reached 73%, with no significant difference from that of Vitamin C; superoxide anion free radical-scavenging activity of theabrownine could be above 60%, which was lower than that of Vitamin C. [Condusion] Liubao tea contains abundant theabrownine that has relatively high antioxidant activity with good prospects in antioxidant application, which lays solid foundation for in-depth development of Liubao tea.

Optimization of Extraction Process of Yingshan Cloud Tea Polysaccharides by Response Surface Methodology

[Objectives] This study was conducted to explore the optimal process conditions for hot water extraction of polysaccharides from Yingshan cloud tea. [Methods] Based on single factor experiments, with the extraction rate of polysaccharides as the response value and liquid-to-solid ratio, extraction temperature and extraction time as investigation factors, the optimum extraction process for tea polysaccharides from Yingshan cloud tea was determined by Box-Behnken central componse design and response surface analysis method. [Results] Under the conditions of the liquid-to-solid ratio of 50∶1(ml/g), the extraction temperature at 94 ℃ and the extraction time of 210 min, the extraction rate of polysaccharides from Yingshan cloud tea reached 2.16%. [Conclusions] This study will provide theoretical basis and reference for subsequent related research.

Investigation on Species of Spiders in Tea Plantations in Enshi Region of China

The spider resources in tea plantations in Enshi region have been investigated and 51 species of spiders belonging to 22 families have been identified in the paper. The dominant species are clarified and their directory and distribution status are also listed in the paper.

Extraction and Quantification of Total Polyphenol Content in Different Parts of Selected Tea Cultivars

Tea (Cammelia sinensis) is the most widely consumed beverage in the world and has been reported to have unlimited health benefits due to its antioxidant properties. There is a high correlation between polyphenol compounds with antioxidant properties. Tea leaves are a major source of polyphenols. The aim of the present investigation was to determine the approximate level of polyphenols in different other parts of the tea plant to give comparative data on obtaining extracts that can be used to design products through value addition to assist in the prevention of diseases associated with oxidative stress. Twenty-one selected region specific tea varieties were used to obtain roots, flowers, leaves and barks. Leaves were prepared by microwaving and the remaining portions processed as green non-aerated teas and black aerated tea. Roots, barks, flowers were sun-dried and milled. Total polyphenol content was determined by calorimetric method using Folin-Ciocalteu reagent. The obtained results suggest that different parts of tea plant have varying numbers of total polyphenols with microwaved leaves having mean levels at 23.1%, steamed leaves (non-aerated green tea) at 22.37%, aerated leaves at 15.51%, barks at 14.92%, flowers at 10.62% and roots at 1.48%.

Optimization of Response Surface of Ultrasonic-assisted Extraction of Rizhao Black Tea

[Objective] The aim was to determine the optimal technology for ultrasonic-assisted extraction of black tea was determined. [Method] Taking Black Tea as materials, the Box-Behnken response surface design method of tea polyphenols ultrasonic-assisted extraction process optimization was applied. The regression optimization model of the ethanol volume fraction, ultrasonic time, and ultrasonic temperature, ethyl acetate extract stalling time and tea polyphenols was established. [Result] The influence of four factors on the black tea polyphenol solvents affecting size was as follows: ultrasonic time > ethanol volume fraction > stalling extraction time > ultrasound temperature. The best extraction process was ultrasonic time 80 min, volume fraction of 88.99% ethanol, extraction time 89.97 min, ultrasonic temperature of 80 ℃. At the optimized technical parameters, the black tea phenolic extraction yield can be as high as 73.50%. [Conclusion] The study provided theoretical basis for the development of tea leaves and black tea.

Canopy Cultivation Technology and Benefit Analysis of Tea Tree Canopy in Preserved Tea Plantations

The present study introduced the concept and characteristics of preserved tea plantation,and analyzed application and benefit of stereoscopic trimming and pruning technology in the cultivation of tea tree canopy in preserved tea plantations.The results show that the stereoscopic trimming and pruning technology of tea trees has more advantages in production efficiency than other trimming and pruning techniques in terms of yield and output value,and can better exert the regeneration ability of tea branches.The grade of branching is increased from grade 3-4 before unpruning to grade 9-13(3-4 times higher),the length of internode is increased from 1-2 cm to 3-7 cm(increased 3-4 times),the picking area is increased from 0.9 m×1.1 m to 2.8 m×4.2 m(an increase of nearly 10 times),accordingly achieving the best production and economic benefits required in tea production.

Influence of Tea Plantations, Forest and Mixed Farming on Stream Flow and Sediment Loads, Case of Sondu Miriu River Basin, Kenya

The changing patterns of land cover and land use in the tropical river basin over time are critical. The hydrological phenomena at basin and sub basin scale are affected positively or negatively by dynamics of the land cover and land use patterns. Hence identifying causes and driving factors aid in taking appropriate measures to avert the impacts. This study determined the influences of sub basins dominated by tea plantations, forests and agricultural land uses in terms of streamflow and sediment flux variability in Sondu Miriu River Basin in Kenya, East Africa. Field-based investigations were conducted through sampling of flow velocities, turbidity and TSSC obtained from existing River Gauging Stations established within the three sub basins. The sub basin dominated by mixed farming land cover exhibits high turbidity approximately 620 NTU and high levels of total suspended sediment concentration (TSSC) of the order of 630 mg/l in wet seasons. The turbidity levels and TSSC were low in sub basins dominated by forest and tea plantations with approximately mean value of 17 - 29 NTU and 0.019 g/l. The sediment loads in sub basin dominated by mixed farming in the pre planting season in January to February were about 900 tonnes/day higher than that in crop growing season. In sub basins dominated by forest cover and tea plantations, sediment loads were low ranging between 2 - 7 tonnes/day. The relationship between stream flows and area under tea plantations, forests and mixed farming ranged between R2 of 0.025 and 0.16. Tea plantations and forests influence the stream flows and sediment yields in long term duration while in mixed farming variations were observed seasonally. The strong relationships between rainfall and stream flows at the sub basins ranging between R2 of 0.84 and 0.97 revealed the significance of rainfall in hydrologic response of the Sondu Miriu River Basin.

Optimization of Supercritical Fluid Extraction of Tea Flower Polysaccharides by Using Response Surface Method

Polysaccharide production from tea flower(TFPS) was carried out using supercritical fluid extraction(SFE).Response surface methodology(RSM),based on a five level,four variable small central composite design,was employed to obtain the best possible combination of extraction time,pressure,temperature and ethanol content of modifier for maximum production.The optimum conditions were as follows:extraction time of 170 min,pressure of45 MPa,temperature of 75 ℃,and 50% aqueous ethanol solution as modifier.Under these conditions,the experimental yield was 6.56 ± 0.37%,which was similar to the value predicted by the model.Monosaccharide composition of TFPS was fucose,rhamnose,arabinose,xylose,galactose,glucose,mannose,fructose,ribose,galacturonic acid and glucuronic acid in a molar percent of 31.69,0.21,0.49,1.29,35.82,0.97,1.63,18.34,7.88,1.06 and 0.63.Compared to other extraction methods,SFE could achieve higher yield and gain more types of monosaccharide.

Multi-Scale Mixed Attention Tea Shoot Instance Segmentation Model

Tea leaf picking is a crucial stage in tea production that directly influences the quality and value of the tea.Traditional tea-picking machines may compromise the quality of the tea leaves.High-quality teas are often handpicked and need more delicate operations in intelligent picking machines.Compared with traditional image processing techniques,deep learning models have stronger feature extraction capabilities,and better generalization and are more suitable for practical tea shoot harvesting.However,current research mostly focuses on shoot detection and cannot directly accomplish end-to-end shoot segmentation tasks.We propose a tea shoot instance segmentation model based on multi-scale mixed attention(Mask2FusionNet)using a dataset from the tea garden in Hangzhou.We further analyzed the characteristics of the tea shoot dataset,where the proportion of small to medium-sized targets is 89.9%.Our algorithm is compared with several mainstream object segmentation algorithms,and the results demonstrate that our model achieves an accuracy of 82%in recognizing the tea shoots,showing a better performance compared to other models.Through ablation experiments,we found that ResNet50,PointRend strategy,and the Feature Pyramid Network(FPN)architecture can improve performance by 1.6%,1.4%,and 2.4%,respectively.These experiments demonstrated that our proposed multi-scale and point selection strategy optimizes the feature extraction capability for overlapping small targets.The results indicate that the proposed Mask2FusionNet model can perform the shoot segmentation in unstructured environments,realizing the individual distinction of tea shoots,and complete extraction of the shoot edge contours with a segmentation accuracy of 82.0%.The research results can provide algorithmic support for the segmentation and intelligent harvesting of premium tea shoots at different scales.

Optimization of Protein Extraction and Decoloration Conditions for Tea Residues

To optimize alkaline method for extracting proteins from tea residue(TR), the effect of extraction conditions on tea protein extraction rate(TPER) was investigated. Single factor experiment showed the extraction temperature 80 °C, extraction time 100 min, p H value 13 and liquid–solid ratio 40:1 as the optimal extraction conditions. The orthogonal test revealed that the maximum TPER reached 29.71% under the following optimal combination of conditions: extraction temperature 70 °C, extraction time 60 min, p H 12 and liquid–solid ratio 50:1. For optimizing the purification of tea residue proteins, isoelectric point precipitation(p I), ammonium sulfate precipitation(a S) and isoelectric point plus ammonium sulfate precipitation(i PAS) were compared. The result showed that the highest protein precipitation rate(PPR) was 89.70% which was generated by using i PAS. Furthermore, powdered activated carbon was chosen as the most suitable decolorant for the extracted proteins.

Study on the microwave-assisted extraction of polyphenols from tea

This study demonstrated a promising method for quickly extracting tea polyphenol(TP)by microwaveassisted extraction(MAE)technology.Some influential parameters,including MAE temperature,microwave power,concentration of extraction solvent,MAE time and the solid/liquid ratio,were investigated.The optimum condition of MAE was obtained by dual extraction with 60%ethanol(v/v)and the solid/liquid ratio 1:12 g/mL at 80℃ for 10 minutes under the microwave power 600W.The yield of TP was 96.5%under the described condition.Compared with traditional methods,including hot reflux extraction(HRE),ultrasound-assisted extraction(UAE)and supercritical fluid extraction(SFE),the extraction time was saved 8 times than that of HRE,and the yield was increased by 17.5%.The extraction time at comparable levels of production was saved 2 times,and the energy consumption was one fourth that of UAE.The extraction time was saved 5 times than that of SFE,and the yield of TP was increased by 40%.Moreover,compared with MAE of TP studied by others,it decreased the solid/liquid ratio from 1∶20 to 1∶12 g/mL without 90-min pre-leaching time,and the yield of TP was increased by 6%-40%.

APPLICATION AND DEVELOPMENT OF ‘GREEN’ PREVENTIVE AND CONTROL TECHNOLOGIES IN GUIZHOU TEA PLANTATIONS

The application and development of ‘green’ preventive technologies in teaplantations is an important means of ensuring tea quality and ecologicalsafety. Ecological, agronomic and biological controls are the main preventivemeasures used in Guizhou Province. This paper summarizes the ‘green’preventive technologies being applied in Guizhou tea plantations, including theuse of plant defense inducers to regulate tea plant responses to pathogens,natural enemies to control pest species causing damage to shoots andTrifolium repens to control the main weed species. In addition, it summarizesthe integrated ‘green’ preventive technologies being used in Guizhou andprovides a foundation for the ecological maintenance of tea plantations.

Ultrasound-assisted extraction of bound phenolic compounds from the residue of Apocynum venetum tea and their antioxidant activities

Bound phenolic compounds from the residue of Apocynum venetum(A.venetum)tea were released by alkaline digestion with sonication,followed by extraction using ethyl acetate(EtOAc).The fragment ions of compounds in free and bound forms were identified by liquid chromatography electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS)in both positive and negative modes.Further investigation of chemical constituents in the EtOAc extract led to the isolation of eleven individual compounds,and their chemical structures were identified as(−)-epicatechin(1),(−)-loliolide(2),(−)-syringaresinol-4-O-β-D-glucopyranoside(3),alloside of benzyl alcohol(4),3-[(6-O-hexopyranosylhexopyranosyl)oxy]-2-(palmitoyloxy)propyl(9Z,12Z,15Z)-9,12,15-octadecatrienoate(5),apocynoside I(6),quercetin-3-O-β-D-glucopyranoside(7),kaempferol-3-O-β-D-glucopyranoside(8),[1-acetyloxy-3-[3,4,5-trihydroxy-6-[[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxymethyl]oxan-2-yl]oxypropan-2-yl]hexadecanoate(9),1-stearoyl-2-palmitoyl-sn-glycerol(10),and 3-hexene-l-O-β-D-glucoside(11)using a series of spectroscopic methods.Compounds 2–5 and 9–11 were isolated for the first time from A.venetum,while antioxidant experiments showed that compounds 1,7,and 8 displayed strong DPPH and ABTS+radical scavenging activities.This study represents the first investigation of bound phenolic compounds with potential health benefits in the residue of A.venetum tea.

青砖茶感官审评方法比较分析

为提出适合青砖茶的感官审评方法,本实验以湖北代表性青砖茶作为研究对象进行煮泡(浸泡式煮茶和喷淋式煮茶),分析不同煮泡条件对青砖茶感官品质及主要品质成分浸出率的影响,并与现行国家标准中冲泡法所得茶汤的感官品质和化学成分进行比较。结果表明,对于紧压型青砖茶,煮泡法茶汤的感官品质明显优于国标冲泡法,煮泡法茶汤的水浸出物、茶多酚、氨基酸、可溶性糖和茶色素等主要品质成分的浸出率远高于国标冲泡法。综合感官品质和品质成分浸出率分析,采用浸泡式煮茶法,在1∶80茶水比、煮沸2 min、静置2~4 min条件下制备的青砖茶茶汤浓度适中,内质品质呈现较为全面。进一步的相关性分析结果表明,可溶性糖、茶褐素及水浸出物浸出率与滋味品质的相关系数较高。该研究结果可为青砖茶及其他类型紧压茶感官品质的客观性评价提供参考。

茶叶烟用香料的制备技术及其在卷烟中的应用进展

综述了茶叶种类和物质组成、茶叶烟用香料制备技术及其在卷烟中的应用现状。茶叶中富含的茶多酚、茶多糖、茶氨酸、茶色素、挥发性成分是茶叶和茶叶烟用香精滋味和功效差异的物质基础。溶剂提取与蒸馏、膜分离技术、超临界二氧化碳萃取、亚临界萃取等技术被应用于茶叶烟用香料的制备,且在叶组、滤棒、内衬纸和卷烟胶有广泛的研究和应用。因此对茶叶烟用香料的现有研究进行归纳总结,并对未来研究方向进行展望分析。

施肥类型对茶园土壤酸度的影响研究

【目的】茶园土壤酸化是当前茶叶生产中面临的重要问题。研究施肥类型对茶园土壤酸度的影响,为茶园土壤酸化阻控和改良提供理论依据。【方法】对比福建省周宁县17个定位监测茶园2013年和2021年土壤酸度变化,并根据相应茶企施肥档案资料,将茶园施肥类型划分为无机型(纯化肥施用)、有机无机型(有机肥和化肥配合施用)、有机型(纯有机肥施用)等3种类型,分析不同施肥类型对茶园土壤酸度的影响。【结果】2013—2021年,无机型肥料管理模式茶园0~20 cm、20~40 cm土层土壤pH平均值分别降低0.26和0.24个单位,年均降低0.033和0.030个pH单位,土壤酸化程度加剧。有机无机型茶园土壤pH分别提高0.19和0.20个单位,年均提高0.024和0.025个pH单位;有机型茶园土壤pH分别提高0.39和0.23个单位,年均提高0.048和0.028个pH单位,土壤酸化得到缓解和改良。茶园土壤pH变化速率与化肥施用量呈极显著的正相关关系,而与有机肥施用量呈极显著的负相关关系,施氮量增加加速茶园土壤酸化,增施有机肥可以减缓和改良土壤酸化。茶园土壤pH变化速率与初始土壤基本理化性状相关关系不显著。【结论】施肥类型是影响茶园土壤酸度变化的主要因素。在茶叶生产中,可通过控制化肥施用量,增加有机肥施用量来阻控和改良茶园土壤酸化。

超声波法提取恒山黄芪叶茶黄酮最佳工艺研究

目的探索超声波法提取黄芪叶茶中黄酮的最优方法。方法利用超声波辅助提取法结合单因素试验和正交试验,确定提取恒山黄芪叶茶中黄酮的最佳提取工艺。结果因素影响力排序:料液比>乙醇浓度>超声波功率>提取温度>提取时间。得到最佳提取工艺为:料液比为1∶35 g/mL,乙醇浓度为60%,超声波功率为280 W,提取温度为60℃,提取时间为45 min。结论在此最佳条件下,恒山黄芪叶茶中总黄酮的提取率为14.302%。